AVFoundation Extensions Improvements

[orchetect]

Currently, extension methods in TimecodeKit on AVFoundation objects (AVAsset, AVAssetTrack, AVMovie) are somewhat limited as far as reading and writing timecode track information.

1. Improve/Extend Functionality

Multiple timecode events are possible in a single timecode track, especially if a video track contains multiple edits.

The current implementation (as of TimecodeKit 2.0.10) covers the essential functionality of:

• reading timecode track(s) and returning the start timecode (startTimecode())
• reading all timecode event(s) from all timecode track(s) (timecodes())
• writing a timecode track using a single origin timecode (addTimecodeTrack() / replaceTimecodeTrack())

Ideally, support would be added for:

• writing complex timelines with more than one timecode event
  • add an overload for addTimecodeTrack() and replaceTimecodeTrack() that takes a dictionary of [TimeInterval: Timecode] or something akin to it, keyed by time offsets from movie start with the timecode as values

2. Improve async/await Support

Numerous AVFoundation methods being used by TimecodeKit in order to read/write AVAsset/AVMovie data are using legacy (deprecated) synchronous methods on AVFoundation objects. It would be ideal to add async variants to TimecodeKit methods to use the newer asynchronous counterparts.